Ok, so i completed fitting the turbo, and got it running.
FAIL.
No matter what i tried, it was getting really bad compressor surge in top gear at high load and low revs.
So i pulled it all out again, and refitted the original setup to get it running for drag day.
I did swap the exhaust housing with my spare, as i found a tiny crack in the one i was using.
For some reason this supposedly identical part seems to be boosting and running better than it did before!?
Ah well. ran it on drag day, and overall pretty happy with the results.
Run 12 passes all day, and the difference between my slowest pass and fastest pass were a mere 0.27 of a second.
Also managed to win the DYO competition again this year too.
Best run was 14.26s @ 102 MPH which bettered last years attempt at 14.4s.
I guess lesson learnt, if it aint broke, dont fuck with it!